Tanzanite vs Sapphire: What Are They, And What's The Difference?

Tanzanite and Sapphire are two of the most beautiful stones and minerals, highly regarded for their aesthetic appeal.

Both Tanzanite and Sapphire can be confused with each other due to their vibrant coloring and use in jewelry.

However, the two minerals have several striking differences that you should know about.

Tanzanite vs Sapphire (EXPLAINED)

What is Tanzanite?

Tanzanite is a variety of zoisite mineral found only in the mountains of northern Tanzania.

It was only recently discovered in 1967 in the hills of Merelani, and was named by Tiffany & Co. in honor of the tribesman that found the gem and their country of origin.

Tanzanite is extremely rare, and can only be mined in this specific location.

In fact, it is considered rarer than diamond.

Besides its striking blue-ish violent or violet-ish blue coloring, this mineral has other unique physical properties.

Tanzanite Coloring

Tanzaite is a name given to zoisite minerals with the specific blue or violet coloring.

This is similar to red corundum minerals “rubies,” or green beryl minerals “emeralds.”

Tanzanite gets its unique coloring from small amounts of vanadium within the zoisite mineral structure.

Tanzanites can be either heat-treated to get that gorgeous blue color out of them, or it can occur naturally.

However, most Tanzanite gems today are heat-treated to about 600 degrees Celsius for a half hour to get their blue color.

Some jewelers hold naturally-colored Tanzanite in high regard due to the amount of heat-treated Tanzanite readily available today.

Tanzanite as a Mineral

Unlike rocks, minerals are solid chemical compounds with well-defined crystal structures.

They occur naturally in their pure form.

Tanzanite is made out of the mineral Zoisite.

Zoisite is a mineral with the chemical formula Ca₂Al₃O(OH), and is composed of hydroxyl silicate of calcium and aluminum.

Zoisite, like most other minerals, can be found within rocks, specifically metamorphic and pegmatitic rocks.

These rocks are made as a result of high heat and volcanic activity, hence naturally colored Tanzanite that occurs from the high heat during volcanic activity.

Physical Properties of Tanzanite

Like all gems, Tanzanite has its own physical properties including durability, hardness, and structure.

Tanzanite is a pleochroic gem, meaning it is viewed as being different colors from different angles!

In Tanzanite, three distinct colors emerge when the gem is viewed from three different directions.

Because of its unique structure, having one direction of perfect cleavage, Tanzanite is prone to breaking.

Although it is durable, it rates a 6 or 7 out of 10 on the Mohs hardness scale.

What is Sapphire?

Sapphire is also a naturally occurring mineral that is hailed for its deep blue coloring.

It is considered to be the most famous engagement ring- that of princess Diana of Wales!

Traditional deep blue sapphires come from the mountains of Kashmir in India, and are very rare.

However, they can be mined in streams in small concentrations.

Sapphire Coloring

The blue coloring in sapphire comes from small amounts of iron and titanium in corundum.

Although the traditional sapphire is blue, other sapphires can result in different colors as a result of impurities in corundum.

These include pink sapphires, green sapphires, even yellow sapphires.

These are commonly know in the jewelry business as “fancy sapphires.”

Sapphire as a Mineral

Sapphire comes from the mineral corundum, which is the same mineral that rubies come from. Corundum has the chemical property Al₂O₃, and is composed of Aluminum and Oxygen.

Corundum minerals are mostly found within metamorphic rocks such as schist and gneiss.

They can also be found in igneous rocks such as basalt or syenite.

However, due to corundum being extremely sensitive to breakage, gem-grade sapphires are rarely found within rocks.

Instead, through millions of years of erosion, these gems have been freed from their rocks and washed down streams and into river beds.

Mining the stream sediments and washing the gravels of these stream deposits makes it easier to find sapphires and rubies.

Physical Properties of Sapphires

Like other gems, sapphires have their own physical and chemical properties.

Its number on the Moh’s hardness scale is 9, making it a very durable mineral.

Sapphires also have a unique rutile needles intersecting them throughout.

Rutile is composed of mostly Titanium Dioxide, and gives sapphire the appearance of silk under a microscope.

Rutiles also allows Sapphires to have their sparkle!

What’s the Same About the Two?

The most common reason Tanzanite and Sapphire are confused is due to their beautiful blue coloring.

Although both minerals can be treated with heat in the jewelry world, Tanzanite is usually treated with heat to give it a deeper blue color, while Sapphire is treated with heat to improve the sapphire’s color and clarity.

Both minerals get their coloring from different impurities within their minerals, with Tanzanite being an impure form of zoisite, and Sapphire being an impure form of corundum.

Both are also used as birthstones and gems, and can be cut to be either large or small.

What’s the Difference Between the Two?

There are incredible differences between the two minerals.

For starters, they both originate from different minerals and from different impurities within those minerals.

Tanzanite is also considered more rare than sapphire, as it only originates in the Merelani hills of Tanzania.

Tanzanite has only recently been discovered, while Sapphire has been around since 1865 when they were first discovered in Montana.

In addition, both are used for different purposes in the jewelry business. Tanzanite is not as hard as Sapphire, having a Moh’s hardness rating of 6 compared to Sapphire’s 9 rating.

This makes Tanzanite prone to breaking, and as such, it is not good to use in rings and other jewelry that will be making contact with continuous abrasive materials.

Sapphire, on the other hand, is far stronger, and can be used readily in rings, brooches, necklaces, and other dress wear.

Appreciating Both

When it comes to Tanzanite and Sapphire, both Tanzanite and Sapphire are gorgeous gems to behold. Both are also rare, and quite a bit pricey.

No matter their differences, one can appreciate the beauty of these minerals.